JPH11110368A - Integrated circuit device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make low voltage, acceleration and low power consumption in an integrated circuit which is provided with a boosting circuit and an oscillator circuit, boosts external power supply internally and operates. SOLUTION: This device is provided with a booster circuit 2 which boosts power supply voltage, an oscillator circuit 1 and a constant current circuit 4 and supplies drive power to a load circuit 3. In such cases, the circuit 1 supplies a clock c that occurs to the circuits 3 and 2, the circuit 2 gives voltage VSS2 that boosts power supply voltage as a voltage control signal b to the circuit 4, and the circuit 4 gives voltage VSS4 that corresponds to the signal b to the circuits 1 and 3 and also gives prescribed constant current d to the circuits 1 and 3. By this, the low power consumption of the boosting circuit and the acceleration and low power consumption of the circuits 1 and 3 are realized.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor integrated circuit (an integrated circuit having a built-in booster circuit and a constant current circuit) used for a portable terminal requiring low voltage operation and low power consumption.

[0002]

2. Description of the Related Art In recent years, there has been a need to reduce the size of equipment, extend the life of a battery, and reduce the number of batteries used. Power consumption is required. In semiconductor integrated circuits, especially microcomputers,
By incorporating a booster circuit and a constant voltage circuit with the reduction of the power supply voltage, it is intended to realize a lower voltage, higher speed, and lower power consumption.

A conventional semiconductor integrated circuit used for a portable terminal or the like which requires low voltage operation and low power consumption is disclosed in Japanese Patent Application Laid-Open No. 8-185240. FIG.
FIG. 1 is a diagram illustrating an example of an integrated circuit that achieves low voltage, high speed, and low power consumption by using a conventional booster circuit and a constant voltage circuit. In FIG. 3, 2 is a booster circuit for boosting an external power supply, 7 is a constant voltage circuit that outputs a constant voltage using the voltage boosted by the booster circuit as a power supply, 1 is an oscillation circuit that uses the output of the constant voltage circuit as a power supply, Reference numeral 3 denotes a load circuit such as a central processing unit (hereinafter abbreviated as "CPU") using the output of the constant voltage circuit as a power supply, and 6 denotes a start-up circuit connected to the output of the constant voltage circuit. Here, the oscillation circuit 1, the booster circuit 2,
The load circuit 3 and the constant voltage circuit 7 have a circuit configuration based on the power supply voltage VDD.

[0004] The operation of the portable terminal configured as described above will be described. First, the start-up circuit 6 operates in response to a reset signal a supplied from the load circuit 3 or a reset signal supplied from the outside, and supplies a constant voltage VSS (GND) to the oscillation circuit 1. The oscillation circuit 1 operates by supplying the constant voltage VSS (GND), and outputs a predetermined clock signal c. The clock signal c is supplied to the booster circuit 2 via the load circuit 3, and the booster circuit 2 operates. The booster circuit 2 generates a voltage VSS2 higher than VSS (GND), and is supplied to the constant voltage circuit 7. The constant voltage circuit 7 outputs a constant voltage VSS3 using the boosted voltage VSS2 as a power supply voltage, and the output voltage VSS3 of the constant voltage circuit 7 is supplied as a power supply voltage to the oscillation circuit 1 and the load circuit 3 such as a CPU. .

Thus, a predetermined constant voltage can always be supplied to the oscillation circuit 1 and the load circuit 3 such as a CPU even when the external power supply voltage is low. This allows
The oscillation circuit 1 and the load circuit 3 can not only operate at high speed, but also can keep power consumption constant irrespective of an external power supply voltage value, thereby realizing low power consumption. Further, even when the output of the booster circuit at the start of oscillation is unstable due to the start-up circuit, the output voltage can be kept constant, so that the oscillator circuit 1 and the load circuit 3 such as the CPU can be driven stably without malfunction. .

[0006]

In recent years, higher speed and lower power consumption have been demanded for semiconductor integrated circuits used in portable terminals and the like that require low voltage operation and low power consumption. However, in the conventional circuit configuration, the load characteristics and current consumption characteristics of the booster circuit 2 have reached the limits of high speed and low power consumption. If the speed is further increased with the conventional circuit configuration, the power consumption of the load circuit 3 such as the oscillation circuit 1 and the CPU increases. The reason is that the operating voltage VSS
This is because, even if the frequency of the oscillation circuit 1 is constant, the current consumption of the oscillation circuit 1 and the load circuit 3 increases due to the increase in the frequency. In addition, it is necessary to increase the output voltage VSS3 of the constant voltage circuit 7 and increase the operating voltage applied to the oscillation circuit 1 and the load circuit 3 due to the increase in speed, so that the power consumption of the oscillation circuit 1 and the load circuit 3 increases. Is also a problem.

When the current consumption of the oscillation circuit 1 and the load circuit 3 increases, the constant voltage circuit 7, which is the power supply of the load circuit 3,
It is also necessary to increase the current driving capability (load characteristics) of the booster circuit 2. However, in order to increase the current driving capability (load characteristics) of the booster circuit 2, it is necessary to increase the clock frequency of the booster circuit 2. (However, in order to increase the current driving capability of the booster circuit 2, depending on the method of the booster circuit 2, the capacity for charging and discharging the charge is increased, or the resistance value of the output transistor of the booster circuit 2 is increased. There is also a method of reducing the time constant of the booster circuit 2 by reducing the wiring resistance and the wiring capacitance.) The current consumption of the booster circuit 2 also increases due to the increase in the clock frequency. In particular, the booster circuit 2
Is a boosted voltage VSS2 higher than the external power supply voltage.
, The current consumption increases significantly.

The present invention has been made to solve the above-mentioned conventional problems, and has a lower voltage operation than a conventional circuit configuration.
It is an object of the present invention to provide an integrated circuit that can realize higher speed and lower power consumption.

[0009]

According to another aspect of the present invention, there is provided an integrated circuit including a booster circuit, an oscillator circuit, and a constant current circuit, wherein a clock generated by the oscillator circuit is connected to the load circuit and the booster circuit. Supplied to the circuit, the booster circuit boosts a power supply voltage, the constant current circuit uses the voltage boosted by the booster circuit as a voltage control signal, and outputs a voltage corresponding to the voltage control signal to the oscillation circuit and the load. Give to the circuit,
A predetermined constant current is supplied to the oscillation circuit and the load circuit.

With this configuration, an oscillation circuit, a load circuit,
The power consumption of the booster circuit can be reduced, the speed of the oscillation circuit and the load circuit can be increased, and the noise can be reduced by reducing the amplitude level of each signal.

According to another aspect of the present invention, there is provided an integrated circuit including a booster circuit, an oscillator circuit, and a constant current circuit, wherein a clock generated by the oscillator circuit is supplied to the load circuit and the booster circuit. The booster circuit boosts a power supply voltage, the constant current circuit sets a voltage boosted by the booster circuit as a power supply voltage, supplies the power supply voltage to the oscillation circuit and the load circuit, and supplies a predetermined constant current to the oscillation circuit and the load circuit. It is provided to an oscillation circuit and the load circuit.

With this configuration, the oscillation circuit, the load circuit,
The power consumption of the booster circuit can be reduced, the speed of the oscillation circuit and the load circuit can be reduced, and the noise can be reduced by reducing the amplitude level of each signal. Therefore, it becomes easier to operate at a lower voltage.

Next, an integrated circuit according to the present invention includes a start-up circuit, wherein the start-up circuit supplies a predetermined voltage to the oscillation circuit in place of the constant current circuit during a certain period of rising, and After the elapse, it is preferable that the constant current circuit supplies a predetermined voltage to the oscillation circuit.

With this configuration, since the start-up circuit is used, the output voltage can be fixed even when the output of the booster circuit is unstable at the start of oscillation.
U and other load circuits can be driven without malfunction.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. (Embodiment 1) FIG. 1 is a block diagram of an integrated circuit according to Embodiment 1. In FIG. 1, reference numeral 1 denotes an oscillation circuit, 2 denotes a booster circuit, and 3 denotes a load circuit such as a CPU. These are the same components as the conventional example shown in FIG. However, the connection relationship between the components is different. Numeral 4 denotes a constant current circuit, which is not included in the conventional configuration. The configuration is such that the constant current circuit, the output voltage of the booster circuit 2, the power supply of the oscillation circuit 2, and the power supply of the load circuit 3 are connected. In the present embodiment, as shown in FIG.
The booster circuit 2 has a circuit configuration based on the power supply voltage VDD, and the booster circuit 2 changes the VSS side. Further, the constant current circuit 4 is configured to limit the amount of current d flowing into the VSS side.

Next, the connection relationship between the components will be specifically described. The output b (VSS2) of the booster circuit 2 is connected as an output control voltage signal of the constant current circuit 4. The output (clock signal c) of the oscillation circuit 1 is input to the booster circuit 2 via the load circuit 3. The control signal a is input from the load circuit 3 to the constant current circuit 4 via the signal line, and the oscillation circuit 2
And the output current d of the load circuit 3 is connected to the constant current circuit 4.

The operation of the integrated circuit according to the first embodiment configured as described above will be described. First, by turning on the power,
The oscillation circuit 1 performs a predetermined oscillation operation at the external power supply voltage level VSS (GND). Next, the clock signal c from the oscillation circuit 1 is supplied to the booster circuit 2 via the load circuit 3, and the booster circuit 2 operates. The booster circuit 2 has a predetermined output voltage VS
S2 is generated as an output b. Specifically, the booster circuit 2
Is a voltage obtained by shifting the potential of
Since the potential of SS is 0 V, a larger voltage control signal is given to the constant current circuit 4. Since the constant current circuit 4 is connected to the power supplies of the oscillation circuit 1 and the load circuit 3, the constant current circuit 4 applies the voltage VSS4 corresponding to the current amount d of the constant current circuit 4 corresponding to the applied voltage control signal VSS2 to the oscillation circuit 1 and the load. This is given to the circuit 3. By using the output b of the booster circuit 2 as described above, the voltage control of the constant current circuit 4 can be performed even at a low voltage, and the operating range of the constant current circuit 4 can be expanded.

Next, a reset signal is generated when the power is turned on. This reset signal may be generated from the load circuit 3 such as a CPU, or may be supplied from outside. A counter circuit (not shown) provided inside the load circuit 3 based on the reset signal, after a certain period of time has elapsed (the time from when the booster circuit 2 is turned on until the operation is stabilized), the load circuit 3 Is supplied to the constant current circuit 4 through the signal line. The constant current circuit 4 controls the current d on the VSS side of the oscillation circuit 1 and the load circuit 3 to a constant amount according to the control signal a.

As described above, according to the first embodiment,
The constant current circuit 4 generates a voltage V according to the voltage control signal VSS2.
By supplying SS4 and a predetermined constant current d to the oscillation circuit 1 and the load circuit 3, the current consumption of the oscillation circuit 1 and the load circuit 3 can be controlled, and the current consumption can be reduced as compared with the conventional voltage control method. Therefore, further lower power consumption can be promoted. If the current consumption is the same, the operation speed of the oscillation circuit and the load circuit can be further increased.

Further, by reducing the current consumption of the oscillation circuit 1 and the load circuit 3, the current driving capability (load characteristic) of the booster circuit 2 can be reduced, the clock frequency can be reduced, and the current consumption can be suppressed. This is particularly effective when the speed of the oscillation circuit 1 and the load circuit 3 is increased and the current driving capability (load characteristic) of the booster circuit 2 is increased due to an increase in the load of the load circuit 3.

(Embodiment 2) FIG. 2 shows Embodiment 2 of the present invention.
1 is a block diagram of an integrated circuit according to the first embodiment. FIG.
1, 1 is an oscillation circuit, 2 is a booster circuit, 3 is a load circuit such as a CPU, 6 is a start-up circuit, and these are the same components as the conventional example shown in FIG. However, the connection between the components is different. 4 is a constant current circuit,
This is similar to that shown in the first embodiment. The output of the booster circuit is connected as the power source of the constant current circuit 4, and the power source of the constant current circuit 4, the power source of the oscillation circuit 2, and the power source of the load circuit 3 are connected. Also in the second embodiment, as in the first embodiment, as shown in FIG. 2, the oscillation circuit 1 and the booster circuit 2 have a circuit configuration based on the power supply voltage VDD, and the booster circuit 2 changes the VSS side. It has a configuration. Further, the constant current circuit 4 is configured to limit the amount of current d flowing into the VSS side.

Next, the connection relationship between the components will be specifically described. The output b (VSS2) of the booster circuit 2 is connected as a power supply of the constant current circuit 4. The output (clock signal c) of the oscillation circuit 1 is input to the booster circuit 2 via the load circuit 3. Further, the control signal a is input from the load circuit 3 to the start-up circuit 5 via a signal line. Further, a startup circuit 6 is connected between the output of the booster circuit 2 and the ground potential 5.

The operation of the integrated circuit according to the second embodiment configured as described above will be described. First, a reset signal is generated when the power is turned on. This reset signal may be generated from the load circuit 3 such as a CPU, or may be supplied from outside. A counter circuit (not shown) provided inside the load circuit 3 based on the reset signal, after a certain period of time has elapsed (the time from when the booster circuit 2 is turned on until the operation is stabilized), the load circuit 3 Is supplied to the start-up circuit 6 through the signal line. Startup circuit 6 receives control signal a and fixes output b of booster circuit 2 to ground potential 5. Thereby, the oscillation circuit 1
Performs an oscillation operation at the external power supply voltage level VSS (GND).

Next, the clock signal c from the oscillation circuit 1 is supplied to the booster circuit 2 via the load circuit 3 and the booster circuit 2
Works. The booster circuit 2 generates a predetermined output voltage VSS2 as an output b. Specifically, this is a voltage obtained by shifting the potential of the booster circuit 2 to the negative potential side. Since the potential of VSS is 0 V, a larger power supply voltage is applied to the constant current circuit 4, and this VSS2 oscillates. This is applied to the circuit 1 and the load circuit 3 and gives a larger voltage. Next, the constant current circuit 4 receives the cancellation of the operation of the start-up circuit 6 based on the control signal a, and
And the consumption current d flowing into the VSS side of the load circuit 3 is limited.

As described above, according to the second embodiment,
As in the first embodiment, the operation of reducing the power consumption of the oscillation circuit, the load circuit, and the booster circuit, increasing the speed of the oscillation circuit and the load circuit, and reducing the noise by reducing the signal amplitude level of each of the oscillation circuit and the load circuit can be realized. Have. Further, since the output of the booster circuit whose power supply voltage has been boosted is used as the power supply of the constant current circuit 4, a lower voltage operation is more easily performed. Further, since the startup circuit 6 is used, even when the output of the booster circuit 2 at the start of oscillation is unstable, the output voltage can be fixed, so that the oscillation circuit and the load circuit such as the CPU can be driven without malfunction.

In the first and second embodiments,
Although the configuration in which the VSS side is changed by the booster circuit 2 as the VDD-based circuit configuration for the power supply has been described, the present invention is not limited to this, and the booster circuit 2 may have a VSS-based circuit configuration. Further, the current limit by the constant current circuit 4 is set to VS.
Although described on the S side, the present invention is not limited to this, and the current limit by the constant current circuit 4 may be a circuit configuration on the VDD side.

[0027]

The integrated circuit device according to the present invention can control the current consumption of the oscillation circuit and the load circuit more easily than the conventional voltage control system, and can promote lower power consumption. With the same current consumption, the operating speed of the oscillation circuit and the load circuit can be increased.

Further, since the current consumption of the oscillation circuit and the load circuit is reduced, the current driving capability (load characteristic) of the booster circuit can be reduced, and the current consumption can be suppressed. In particular, it is effective when the current drive capability (load characteristics) of the booster circuit is increased due to an increase in the speed of the oscillation circuit and the load circuit and an increase in the load of the load circuit. Further, the speed of the oscillation circuit and the speed of the entire integrated circuit can be increased. Further, a larger-scale load circuit can be driven by reducing the current driving capability (load characteristics) of the booster circuit.

Further, since the amplitude level of each signal in the oscillation circuit / load circuit can be further suppressed, the radiation noise from the integrated circuit can be further reduced. Further, a start-up circuit can be eliminated, the circuit configuration can be simplified, and the size of the integrated circuit can be reduced.

[Brief description of the drawings]

FIG. 1 is a block diagram of an integrated circuit according to a first embodiment of the present invention;

FIG. 2 is a block diagram of an integrated circuit according to a second embodiment of the present invention;

FIG. 3 is a block diagram of a conventional integrated circuit.

[Explanation of symbols]

 Reference Signs List 1 oscillation circuit 2 booster circuit 3 load circuit such as CPU 4 constant current circuit 5 ground potential 6 start-up circuit 7 constant voltage circuit

Claims (3)

[Claims] 1. An integrated circuit device comprising a booster circuit, an oscillator circuit, and a constant current circuit for supplying drive power to a load circuit, wherein a clock generated by the oscillator circuit is supplied to the load circuit and the booster circuit. The booster circuit boosts a power supply voltage, the constant current circuit uses the voltage boosted by the booster circuit as a voltage control signal, and supplies a predetermined constant current according to the voltage control signal to the oscillation circuit and the load. An integrated circuit device provided to a circuit. 2. An integrated circuit device comprising a booster circuit, an oscillator circuit, and a constant current circuit for supplying drive power to a load circuit, wherein a clock generated by the oscillator circuit is supplied to the load circuit and the booster circuit. The booster circuit boosts a power supply voltage, and the constant current circuit uses the voltage boosted by the booster circuit as a power supply voltage, applies the power supply voltage to the oscillation circuit and the load circuit, and supplies a predetermined constant current. An integrated circuit device provided to the oscillation circuit and the load circuit. 3. A start-up circuit, wherein the start-up circuit supplies a predetermined voltage to the oscillation circuit in place of the constant current circuit for a certain period of rising, and after the certain period elapses, the constant current circuit 3. The integrated circuit device according to claim 1, wherein a predetermined voltage is supplied to the oscillation circuit.